<big id="9upoa"><xmp id="9upoa"><big id="9upoa"></big>
  • <nobr id="9upoa"></nobr>
    <center id="9upoa"><small id="9upoa"><center id="9upoa"></center></small></center>
  • 參數(shù)資料
    型號: AD5228BUJZ50-RL7
    廠商: Analog Devices Inc
    文件頁數(shù): 7/20頁
    文件大?。?/td> 0K
    描述: IC DGTL POT 50K UP/DN TSOT23-8
    標準包裝: 3,000
    接片: 32
    電阻(歐姆): 50k
    電路數(shù): 1
    溫度系數(shù): 標準值 35 ppm/°C
    存儲器類型: 易失
    接口: 2 線按鈕
    電源電壓: 2.7 V ~ 5.5 V
    工作溫度: -40°C ~ 105°C
    安裝類型: 表面貼裝
    封裝/外殼: SOT-23-8 薄型,TSOT-23-8
    供應商設備封裝: TSOT-23-8
    包裝: 帶卷 (TR)
    配用: EVAL-AD5228EBZ-ND - BOARD EVAL FOR AD5228 DGTL POT
    AD5228
    Rev. A | Page 15 of 20
    APPLICATIONS
    MANUAL ADJUSTABLE LED DRIVER
    The AD5228 can be used in many electronics-level adjustments
    such as LED drivers for LCD panel backlight controls. Figure 41
    shows a manually adjustable LED driver. The AD5228 sets the
    voltage across the white LED D1 for the brightness control.
    Since U2 handles up to 250 mA, a typical white LED with VF of
    3.5 V requires a resistor, R1, to limit U2 current. This circuit is
    simple but not power efficient. The U2 shutdown pin can be
    toggled with a PWM signal to conserve power.
    04422-
    0-
    042
    PUSH-UP
    BUTTON
    PUSH-DOWN
    BUTTON
    A
    W
    B
    10k
    Ω
    VDD
    GND
    PRE
    PU
    PD
    U1
    AD5228
    C1
    1
    μF
    C2
    0.1
    μF
    5V
    U2
    AD8591
    +
    V+
    V–
    SD
    5V
    C3
    0.1
    μF
    R1
    6
    Ω
    WHITE
    LED
    D1
    PWM
    Figure 41. Low Cost Adjustable LED Driver
    ADJUSTABLE CURRENT SOURCE FOR LED DRIVER
    Because LED brightness is a function of current rather than of
    forward voltage, an adjustable current source is preferred as
    shown in Figure 42. The load current can be found as the VWB
    of the AD5228 divided by RSET.
    SET
    WB
    D1
    R
    V
    I
    =
    (7)
    The U1 ADP3333ARM-1.5 is a 1.5 V LDO that is lifted above
    or lowered below 0 V. When VWB of the AD5228 is at its
    minimum, there is no current through D1, so the GND pin of U1
    is at –1.5 V if U3 is biased with the dual supplies. As a result,
    some of the U2 low resistance steps have no effect on the output
    until the U1 GND pin is lifted above 0 V. When VWB of the
    AD5228 is at its maximum, VOUT becomes VL + VAB, so the U1
    supply voltage must be biased with adequate headroom. Similarly,
    PWM signal can be applied at the U1 shutdown pin for power
    efficiency.
    04422-
    0-
    043
    PUSH-UP
    BUTTON
    PUSH-DOWN
    BUTTON
    A
    W
    B
    10k
    Ω
    R1
    418k
    Ω
    VDD
    GND
    PRE
    PU
    PD
    U2
    AD5228
    5V
    U3
    AD8591
    +
    V+
    V–
    5V
    PWM
    VIN
    VOUT
    GND
    U1
    ADP3333
    ARM-1.5
    SD
    RSET
    0.1
    Ω
    VL
    ID
    D1
    Figure 42. Adjustable Current Source for LED Driver
    ADJUSTABLE HIGH POWER LED DRIVER
    The previous circuit works well for a single LED. Figure 43
    shows a circuit that can drive three to four high power LEDs.
    The ADP1610 is an adjustable boost regulator that provides the
    voltage headroom and current for the LEDs. The AD5228 and
    the op amp form an average gain of 12 feedback network that
    servos the RSET voltage and the ADP1610 FB pin 1.2 V band gap
    reference voltage. As the loop is set, the voltage across RSET is
    regulated around 0.1 V and adjusted by the digital
    potentiometer.
    SET
    R
    LED
    R
    V
    I
    SET
    =
    (8)
    RSET should be small enough to conserve power but large enough
    to limit maximum LED current. R3 should also be used in par-
    allel with AD5228 to limit the LED current within an achievable
    range. A wider current adjustment range is possible by lowering
    the R2 to R1 ratio as well as changing R3 accordingly.
    04422-0-044
    SS
    RT GND
    IN
    U2
    ADP1610
    SW
    FB
    PWM
    1.2V
    SD
    COMP
    CSS
    10nF
    CC
    390pF
    RC
    100k
    Ω
    L1
    10
    μF
    D1
    C3
    10
    μF
    R4
    13.5k
    Ω
    D2
    D3
    D4
    VOUT
    C2
    10
    μF
    5V
    +
    AD8541
    U1
    L1–SLF6025-100M1R0
    D1–MBR0520LT1
    U3
    V+
    V–
    5V
    C8
    0.1
    μF
    U1
    AD5228
    BA
    10k
    Ω
    R3
    200
    Ω
    W
    R1
    100
    Ω
    R2
    1.1k
    Ω
    RSET
    0.25
    Ω
    Figure 43. Adjustable Current Source for LEDs in Series
    相關PDF資料
    PDF描述
    VI-BNW-IU-F3 CONVERTER MOD DC/DC 5.5V 200W
    VE-24W-MY-F2 CONVERTER MOD DC/DC 5.5V 50W
    VE-262-MY-F2 CONVERTER MOD DC/DC 15V 50W
    VE-B62-IU-F2 CONVERTER MOD DC/DC 15V 200W
    VE-262-MY-F1 CONVERTER MOD DC/DC 15V 50W
    相關代理商/技術(shù)參數(shù)
    參數(shù)描述
    AD5228EVAL 制造商:AD 制造商全稱:Analog Devices 功能描述:32-Position Manual Up/Down Control Potentiometer
    AD522AD 制造商:Rochester Electronics LLC 功能描述:INSTRUMENTATION AMPLIFIER - Bulk
    AD522B 制造商:AD 制造商全稱:Analog Devices 功能描述:High Accuracy Data Acquisition Instrumentation Amplifier
    AD522BD 功能描述:IC AMP INST 1.5KHZ LDRIFT 14CDIP RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 其它有關文件:TS1854A View All Specifications 標準包裝:50 系列:- 放大器類型:通用 電路數(shù):4 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.25 V/µs 增益帶寬積:630kHz -3db帶寬:- 電流 - 輸入偏壓:16nA 電壓 - 輸入偏移:1000µV 電流 - 電源:162µA 電流 - 輸出 / 通道:48mA 電壓 - 電源,單路/雙路(±):1.8 V ~ 6 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:14-SOIC(0.154",3.90mm 寬) 供應商設備封裝:14-SO 包裝:管件
    AD522SD 制造商: 功能描述: 制造商:undefined 功能描述: